Beneficial effects of iodized salt prophylaxis on thyroid volume in an iodine deficient area of Southern Italy

Objective and subjects Goitre prevalence in school-age children is an indicator of the severity of iodine deficiency disorders (IDD) in an endemic area. The aims of the present study were (i) to provide ultrasound thyroid volume (TV) reference values in a healthy population of school-children aged 11-14 year living in iodine-sufficient areas of Calabria region (ii) to assess both goitre prevalence and urinary iodine (UI) concentration in all children aged 11-14 year from four mildly iodine-deficient areas in which we have carried out a program of salt iodization and (iii) to evaluate the efficacy of the iodoprophylaxis in an adult population living in a small village of the same endemic area. Design Cross-sectional and prospective studies. Methods TV was assessed by ultrasonography and iodine intake was estimated by measuring iodine excretion in spot urine samples. Results We provided the ultrasound normal reference values as a function of age and body surface area, which displayed significant differences from those recommended by the World Health Organization. By adopting local criteria, the prevalence of goitre in children ranged from 23·4% to 27·7% normalized for age and body surface area, respectively, while the UI excretion was < 100 μg/l in 38% of subjects studied. In an adult population living in the same endemic area, goitre prevalence was lowest in the 18-27-year-old age group, and increased progressively with age. Conclusion We propose for the first time local reference ultrasound values for TV in a population of 11-14-year-old school-children that should be used for monitoring IDDs and have demonstrated the beneficial effects of iodoprophylaxis in consistent with reduced goitre prevalence in children and in the young adult population studied.